E4 Error

[paysaw]

I am getting the classic E4 Class error.I re soldered the connections and put the unit in my other bike and it works fine.When I put it on the bike I am working on I get the error.What else could be wrong?Suggestions please/ Thanks

[Great White]

Assuming you fixed the bad solder joints issue, the actual fault code for E4 is "the pressure sensor has no output voltage".

 

But don't start buying/hunting parts yet. The sensor is back on the compressor/valve unit. Head back there and pull the wiring connectors apart and look for signs of corrosion. If any found, clean it up with some contact cleaner and put it back together. See what you get. If it works, bonus. If not, have a look at all the connectors in the system to make sure they are making good contact.

Edited July 6, 2015 by Great White

[paysaw]

Here is the other problem.This 86 bike seems to have a retro fitted class system.When I got it the blue wire for the relay to the compressor was disconnected.I looked the wiring diagram and it said it needed to go to a relay.I installed a relay to the compressor and blue wire from the class harness.Is the blue wire the hot or the ground to the relay?Anyone have an answer? You will have to look at the schematics to see what I am talking about.

[bongobobny]

OK Ray, from what I see from the wiring diagram the relay coil has a Red/Blue wire which goes to the CLASS fuse which would be +, and a Blue/White wire which should supply ground...

[paysaw]

If any of this is disconnected would I get the E4 error Bob?

[bongobobny]

Not sure Ray, never played around disconnecting wires. A disconnected wire will give you some kind of error signal for sure, but not sure which E it would give..

[paysaw]

As it turned out,It was the connector to the Class control was the problem.I had everything right.I installed a relay that was not even in the system.Someone had replaced it with a toggle witch to engage the pump in a real crude way.The system is quite simple.That Lavender wire connects the ground to the relay to turn on the pump.Thanks for your help on this everyone.